Coupling devices of this type are known (WO 91/03347), in which a one-part or multipart clamping bolt is movably arranged in a crossbore of the pin and having an inner or outer cone at its end and two holding screws guided in diametrically oppositely lying internal threads of the coupling sleeve, having an outer or inner cone facing toward the inside of the sleeve, and clamped with the clamping bolt during the clamping operation are provided, with the clamping bolt and the holding screw having an axial misalignment effecting during the clamping operation the pulling of the pin into the recess and the reciprocal pressing of the annular surface against the end surface. The clamping operation is released in the case of these devices, for example, by screwing in the holding screw (clamping screw) provided with the outer cone. If abutment occurs during screwing in of the clamping screw, then the forces introduced through the screw occur first on the side of the clamping screw on the clamping bolt. The clamping bolt is thereby first pressed on the side of the clamping screw against the crossbore base facing the end of the shaft such that the shaft is pulled into the recess. This occurs immediately thereafter also when the clamping bolt outer cone contacts the inner cone of the oppositely lying holding screw. As soon as a specific clamping action has occurred, a complete transformation of the radial forces into an axial component pressing the annular surface of the fitting pin and the end surface of the coupling sleeve against one another takes place. With this type of clamping a reinforcement of the connecting device in direction of the bolt results preferably.
It is furthermore known in a coupling device of the mentioned type (WO 91/03347) to design the clamping bolt in two parts and to release the clamping operation with a sliding wedge arranged between the two clamping-bolt parts and which can be axially operated through a pulling-in device arranged on the side of the machine. Here too takes place during the clamping operation a clamping of the clamping bolts provided with an outer cone and of the holding screws arranged in an internal thread of the coupling sleeve and having an inner cone. The reinforcement of the connecting device occurs here also preferably in direction of the clamping bolts.
In order to increase the resistance to bending transversely with respect to the clamping-bolt axis and in addition in order to improve the changing exactness and the dampening behavior, it is there furthermore suggested to create a four-point bearing between shaft and recess in two directions which are perpendicular to one another. In order to achieve this, the coupling sleeve is elastically expanded during the clamping operation in axial direction of the clamping bolt such that it is pressed in transverse direction thereto under an elastic reduction in diameter in diametrically oppositely lying areas with the inner surface of the recess against the upper surface of the shaft. By suitably selecting the wall thickness and the outside and inside tolerances of the shaft and of the coupling sleeve the desired four-point bearing is obtained in this manner. A further improvement in this respect is achieved by the crossbore in the shaft having a recess in the area of its base facing the end of the pin, which recess forms at its longitudinal edges an abutment for the fixed clamping bolt, and which recess results in a certain bulging of the shaft and thus in a bridging of the tolerance of fit transversely with respect to the direction of the crossbore. This effect is further reinforced by the shaft having at least one slot-shaped groove extending over the length of the crossbore and being open toward the inside of the crossbore. The groove results during the clamping operation in an expanding of the crossbore and thus in a greater bulging of the fitting pin and in the desired self-centering four-point bearing.